1. Field of the Invention
This invention relates generally to a method for diffusion bonding of ceramics, and in particular to a method for forming internal cavities of small dimensions in ceramics by bonding ceramic bodies together.
2. Description of the Background Art
Ceramic microwave components such as phase-shifters and latching switches for use in microwave devices utilize shapes such as toroidal configurations having internal cavity dimensions which are dictated in part by the frequency of the microwaves with which the components are to be used. As present technology advances toward very high frequencies, holes are required in the ceramics having diameters on the order of 0.05 centimeters or less. When such small diameter holes are required with lengths greater than 0.6 cm., it has been found that conventional methods will not reliably produce the desired parts. Such methods include drilling with diamond tipped tools, pressing ceramic powder around a mandrel which is removed before final firing, pressing powder around a burnout insert which is consumed during firing, and laser cutting and drilling of previously fired ceramic masses. These techniques, while useful, especially where small dimensions are not necessary, produce such shortcomings as warping during forming and firing which causes unacceptable dimensional variances. In addition, cracking of parts during firing causes parts to be rejected as unusable after they have been machined. Moreover, intricate shapes are not attainable, and, as pointed out above, holes of small diameter are difficult, if not impossible to produce except in short lengths.
Therefore, it is an object of this invention to provide a method which overcomes the aforementioned inadequacies of the prior art methods and provides an improvement which is a significant contribution to the advancement of the ceramic arts.
Another object of this invention is to permit the forming of cavity configurations in a ceramic body having dimensions usable for microwave components.
It is also an object of this invention to provide a method which will result in a higher percentage of usable parts when small internal cavity configurations are incorporated.
The foregoing has outlined some of the more pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be attained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description of the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.